getKeys

Extracts keys from arrays, objects, and other values with enhanced type safety. Provides a unified interface for key extraction that handles arrays (returning string indices), objects (returning property names), and other types with fallback iteration. Optimized for performance with direct array handling.

Signature

const getKeys: <Value>(value: Value) => string[]

Parameters

Name	Type	Description
value	-	Value to extract keys from (array, object, or other)

Returns

Array of string keys representing indices or property names

Examples

Array key extraction

import { getKeys } from '@winglet/common-utils';

const array = ['a', 'b', 'c'];
console.log(getKeys(array)); // ['0', '1', '2']

const sparseArray = [1, , 3]; // sparse array
console.log(getKeys(sparseArray)); // ['0', '1', '2']

Object key extraction

const obj = { name: 'John', age: 30, city: 'NYC' };
console.log(getKeys(obj)); // ['name', 'age', 'city']

const emptyObj = {};
console.log(getKeys(emptyObj)); // []

Mixed type handling

console.log(getKeys('hello')); // ['0', '1', '2', '3', '4']
console.log(getKeys(123)); // []
console.log(getKeys(null)); // []
console.log(getKeys(undefined)); // []

Playground

import { getKeys } from '@winglet/common-utils';

const array = ['a', 'b', 'c'];
console.log(getKeys(array)); // ['0', '1', '2']

const sparseArray = [1, , 3]; // sparse array
console.log(getKeys(sparseArray)); // ['0', '1', '2']

Notes

Behavior by Type:

• Arrays: Returns string indices ('0', '1', '2', etc.)
• Objects: Returns own enumerable property names
• Strings: Returns character indices
• Other: Uses for...in loop with hasOwnProperty check

Performance: Optimized array handling with pre-allocated string array.